A tri-functionalised PtSnOx-based electrocatalyst for hydrogen generation via ammonia decomposition under native pH conditions.

Hydrogen is one of the most clean energy carriers because water is only the product of its combustion. The electrolysis of ammonia is expected to offer an attractive alternative to water electrolysis for the production of hydrogen because of the lower thermodynamic energy. However, the synthesis and utilization of high-performance Pt electrocatalysts have encountered challenges related to instability and hydroxyl ion sensitivity. To address these issues, we developed PtSnOx-based nanoparticles that maintained high electrocatalytic activity and stability for the decomposition of aqueous ammonia to generate hydrogen under native pH conditions which means the acidity/alkalinity is not adjusted. FT-IR, XRD, and XPS evidence showed PtSnOx was a tri-functionalised electrocatalyst. That is to say, the spherical SnOx nanoparticles assisted ammonia adsorption and activation, which were accompanied by a hydrogen adsorption on PtSnOx and hydrogen transfer along the SnOH bond over the electrocatalyst. According to these data of FT-IR, XRD, and XPS before and after reaction, a possible mechanism for the decomposition of aqueous ammonia to produce hydrogen was proposed. This study could pave the way to prospective routes for the selective oxidation of the NH bond to generate hydrogen under mild conditions.